According to a Fortune story:
. . .a new study from the University of California’s Lawrence Berkeley National Laboratory shows that simply installing white roofs on homes and commercial buildings - to reflect the sun’s rays rather than absorb them - can reduce air-conditioning costs by 20% and could save $1 billion a year in energy outlays in the United States.
Grist goes a little deeper, and takes a larger, city-wide view:
This whole climate-change debacle could be significantly slowed down if the world's 100 largest cities thing installed white roofs and more-reflective pavement. . .By bouncing heat away from the Earth, a 1,000-square-foot white roof offsets 10 metric tons of greenhouse gases. Roofs account for 25 percent of the surface of most cities, and pavement makes up some 35 percent.
Of course, whenever I see a stampede one way or the other on a hot new topic, I suffer an attack of my chronic, early onset skepticism -- especially this one, with its Tom Sawyer overtones.
Regardless of the societal impact, it doesn't seem like a bad idea on its face, especially for manufacturing plants looking to reduce energy spend and carbon footprint reduction.